ISO 9683-2:2009

INTERNATIONAL ISO
STANDARD 9683-2
First edition
2009-06-15
Corrected version
2009-10-01

Iron ores — Determination of
vanadium —
Part 2:
Flame atomic absorption spectrometric
methods
Minerais de fer — Dosage du vanadium —
Partie 2: Méthodes par spectrométrie d'absorption atomique dans la
flamme




Reference number
ISO 9683-2:2009(E)
©
ISO 2009

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ISO 9683-2:2009(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.


COPYRIGHT PROTECTED DOCUMENT


©  ISO 2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
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Published in Switzerland

ii © ISO 2009 – All rights reserved

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ISO 9683-2:2009(E)
Contents Page
Foreword .iv
1 Scope.1
2 Normative references.1
3 Principle.1
3.1 Dissolution .1
3.2 Determination .2
3.2.1 Extraction (Method 1 only) .2
3.2.2 Measurement (Methods 1 and 2).2
4 Reagents.2
5 Apparatus.3
6 Sampling and samples.4
6.1 Laboratory sample .4
6.2 Preparation of predried test samples.4
7 Procedure.5
7.1 Number of determinations.5
7.2 Safety precautions .5
7.3 Test portion.5
7.4 Blank test and check test .5
7.5 Determination Method 1 (mass fraction of vanadium between 0,004 % and 0,06 %).5
7.5.1 Decomposition of the test portion.5
7.5.2 Dissolution of salts and residue treatment.5
7.5.3 Extraction of vanadium.6
7.5.4 Adjustment of the atomic absorption spectrometer.6
7.5.5 Atomic absorption measurements .6
7.6 Determination Method 2 (mass fraction of vanadium between 0,06 % and 0,5 %).7
7.6.1 Decomposition of the test portion.7
7.6.2 Dissolution of salts and residue treatment.7
8 Expression of results.7
8.1 Calculation of mass fraction of vanadium.7
8.2 General treatment of results.8
8.2.1 Repeatability and permissible tolerance.8
8.2.2 Determination of analytical result.8
8.2.3 Between-laboratories precision.9
8.2.4 Check for trueness .9
8.2.5 Calculation of final result.10
8.3 Oxide factor.10
9 Test report.10
Annex A (normative) Flowsheet of the procedure for the acceptance of analytical values for test
samples .11
Annex B (informative) Derivation of repeatability and permissible tolerance equations.12
Annex C (informative) Precision data obtained by international analytical trials.13

© ISO 2009 – All rights reserved iii

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ISO 9683-2:2009(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 9683-2 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron,
Subcommittee SC 2, Chemical analysis.
This first edition cancels and replaces ISO 9684:1991.
ISO 9683 consists of the following parts, under the general title Iron ores — Determination of vanadium:
⎯ Part 1: BPHA spectrophotometric method
⎯ Part 2: Flame atomic absorption spectrometric methods
This corrected version of ISO 9683-2:2009 incorporates the following correction: a new sixth paragraph has
been added to this foreword.
iv © ISO 2009 – All rights reserved

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INTERNATIONAL STANDARD ISO 9683-2:2009(E)

Iron ores — Determination of vanadium —
Part 2:
Flame atomic absorption spectrometric methods
WARNING — This part of ISO 9683 may involve hazardous materials, operations and equipment. This
part of ISO 9683 does not purport to address all of the safety issues associated with its use. It is the
responsibility of the user to establish appropriate health and safety practices and determine the
applicability of regulatory limitations prior to use.
1 Scope
This part of ISO 9683 specifies two flame atomic absorption spectrometric methods for the determination of
the mass fraction of vanadium in iron ores.
Method 1 is applicable to mass fractions of vanadium between 0,004 % and 0,06 %, and Method 2 is
applicable to mass fractions of vanadium between 0,06 % and 0,5 %, in natural iron ores, iron ore
concentrates and agglomerates, including sinter products.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3082, Iron ores — Sampling and sample preparation procedures
ISO 7764, Iron ores — Preparation of predried test samples for chemical analysis
3 Principle
3.1 Dissolution
The test portion is decomposed by digestion with hydrochloric acid in a polytetrafluoroethylene (PTFE) beaker,
hydrofluoric and nitric acids are added and the solution is evaporated to dryness. Hydrochloric and boric acids
are added and the solution is again evaporated to dryness. The salts are dissolved in hydrochloric and nitric
acids (Method 1), or hydrochloric acid (Method 2), and the solution is filtered. The residue is ignited and fused
with sodium carbonate and the cooled melt is dissolved in the test solution.
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ISO 9683-2:2009(E)
3.2 Determination
3.2.1 Extraction (Method 1 only)
The solution is oxidized with cerium(IV) solution, and phosphoric acid and sodium tungstate solution are
added. The vanadium complex is extracted with a 1 + 1 mixture of 1-pentanol and 4-methyl-2-pentanone.
The solvent phase is treated with water and then ascorbic acid solution to return the vanadium to an aqueous
phase.
3.2.2 Measurement (Methods 1 and 2)
Aluminium solution is added to the test solution, which is diluted to volume. The solution is aspirated into a
dinitrogen oxide/acetylene flame in an atomic absorption spectrometer and the absorbance is measured at a
wavelength of approximately 318,5 nm.
4 Reagents
During the analysis, use only reagents of recognized analytical grade, and only distilled water or water of
equivalent purity.
4.1 Hydrochloric acid, ρ 1,16 g/ml to 1,19 g/ml.
4.2 Hydrochloric acid, ρ 1,16 g/ml to 1,19 g/ml, diluted 1 + 1.
4.3 Hydrofluoric acid, ρ 1,13 g/ml, 40 % (by mass) or 1,19 g/ml, 48 % (by mass).
4.4 Nitric acid, ρ 1,4 g/ml.
4.5 Nitric acid, ρ 1,4 g/ml, diluted 1 + 1. (Method 1 only.)
4.6 Phosphoric acid, ρ 1,7 g/ml, diluted 1 + 2. (Method 1 only.)
4.7 Sodium carbonate (Na CO ), anhydrous powder.
2 3
4.8 Boric acid (H BO ).
3 3
4.9 Di-ammonium cerium(IV) nitrate [(NH ) Ce(NO ) ], 20 g/l solution. (Method 1 only.)
4 2 3 6
Dissolve 2,0 g of di-ammonium cerium(IV) nitrate in a mixture of 15 ml of nitric acid (4.5) and 85 ml of water.
4.10 Sodium tungstate (Na WO ⋅ 2H O), 165 g/l solution. (Method 1 only.)
2 4 2
Dissolve 16,5 g of sodium tungstate dihydrate in approximately 70 ml of water, dilute to 100 ml and mix.
4.11 Ascorbic acid (C H O ), 10 g/l solution. (Method 1 only.)
6 8 6
Prepare freshly for each series of tests.
4.12 1-Pentanol (n-amyl alcohol, 1-pentan-1-ol). (Method 1 only.)
4.13 4-Methyl-2-pentanone (methyl isobutyl ketone, MIBK). (Method 1 only.)
4.14 Mixed solvent. (Method 1 only.)
Prepare a 1 + 1 volume ratio mixture of 1-pentanol (4.12) and MIBK (4.13).
2 © ISO 2009 – All rights reserved

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ISO 9683-2:2009(E)
4.15 Aluminium chloride (AlCl ⋅ 6H O), 220 g/l solution.
3 2
Dissolve 220 g of aluminium chloride hexahydrate in water, add 50 ml of hydrochloric acid (4.1), dilute to
1 000 ml with water and mix.
4.16 Iron oxide, high purity (containing less than 0,002 % V).
4.17 Iron background solution. (Method 2 only.)
Dissolve 90 g of high-purity iron oxide (4.16) in 750 ml of hydrochloric acid (4.1) while heating. Cool and
carefully add a solution of 30 g of sodium carbonate (4.7) in 200 ml of water. Dilute with water to a final
volume of approximately 1 000 ml and mix.
NOTE The use of an equivalent quantity of metallic iron (of similarly low vanadium content), in conjunction with a
suitable oxidant, is permissible.
4.18 Vanadium standard solution, 1 mg V/ml.
Dry ammonium monovanadate (NH VO ) in an air oven at 100 ºC for 1 h and cool to room temperature.
4 3
Dissolve 2,296 g of the dried product in approximately 600 ml of water, transfer to a 1 000 ml one-mark
volumetric flask, dilute to volume with water and mix.
4.19 Diluted vanadium standard solution, 0,2 mg V/ml. (Method 1 only.)
Transfer 20,0 ml of vanadium standard solution (4.18) to a 100 ml one-mark volumetric flask, dilute to volume
with water and mix.
4.20 Vanadium calibration solutions. (Method 1 only.)
Transfer 1,8 g of high-purity iron oxide (4.16) to each of five 100 ml PTFE beakers (5.1). Proceed according
to 7.5.1, incorporating the operation in 7.5.2 to dissolve the evaporated salts.
Transfer 0 ml; 1,00 ml; 2,00 ml: 4,00 ml and 6,00 ml of the diluted vanadium standard solution (4.19),
respectively, to the beakers. Omit the residue-processing steps and add 10 ml of nitric acid (4.5) and 25 ml of
water. Evaporate to 50 ml and proceed as specified in 7.5.3.
4.21 Vanadium calibration solutions. (Method 2 only.)
Transfer 0 ml; 1,00 ml; 2,00 ml; 4,00 ml and 6,00 ml of vanadium standard solution (4.18), respectively, to five
100 ml one-mark volumetric flasks. Add 10 ml of iron background solution (4.17), 4,0 ml of aluminium chloride
solution (4.15) and 0,5 g of boric acid (4.8) to each flask. Dilute to volume with water and mix.
5 Apparatus
Ordinary laboratory apparatus, including one-mark pipettes and one mark-volumetric flasks complying with the
specifications of ISO 648 and ISO 1042, respectively (unless otherwise indicated), and the following.
5.1 Polytetrafluoroethylene (PTFE) beakers, of capacity 100 ml, preferably low form.
5.2 Platinum crucibles, of minimum capacity 20 ml.
5.3 Muffle furnace.
5.4 Separating funnels, 100 ml (preferably graduated).
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ISO 9683-2:2009(E)
5.5 Atomic absorption spectrometer, equipped with a dinitrogen oxide/acetylene burner.
The atomic absorption spectrometer used in this method is satisfactory if it meets the following criteria.
a) Minimum sensitivity: the absorbance of the most concentrated vanadium calibration solution (4.21) is at
least 0,25 (see Note 2).
b) Graph linearity: the slope of the calibration graph covering the top 20 % of the concentration range
(expressed as a change in absorbance) is not less than 0,7 of the value of the slope for the bottom 20 %
of the concentration range determined in the same way.
c) Minimum stability: the standard deviation of the absorbance of the most concentrated calibration
solution and that of the zero calibration solution, each being calculated from a sufficient number of
repetitive measurements, are less than 1,5 % and 0,5 %, respectively, of the mean value of the
absorbance of the most concentrated solution.
The use of a strip-chart recorder and/or digital read-out device is recommended to evaluate criteria a), b) and
c) and for all subsequent measurements.
NOTE 1 Instrument parameters:
V-hollow cathode lamp, mA 10
Wavelength, nm 318,5
Dinitrogen oxide flow rate, l/min 9,5
Acetylene flow rate, l/min 3,8
In systems where the values shown above for gas flow rates do not apply, the given ratio of the flow rates (5:2) can still be
a useful guideline.
The slit width should be sufficiently narrow to substantially reject the stronger emitting but weaker absorbing
line at 318,4 nm.
NOTE 2 To check the instrument criteria when only Method 1 is involved, prepare the highest calibration solution
specified fo
...

DRAFT INTERNATIONAL STANDARD ISO/DIS 9683-2
ISO/TC 102/SC 2 Secretariat: SA
Voting begins on: Voting terminates on:
2008-06-06 2008-11-06
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION
Iron ores — Determination of vanadium —
Part 2:
Flame atomic absorption spectrometric methods
Minerais de fer — Dosage du vanadium —
Partie 2: Méthodes par spectrométrie d'absorption atomique dans la flamme
(Revision of ISO 9684:1991)
ICS 73.060.10

In accordance with the provisions of Council Resolution 15/1993 this document is circulated in
the English language only.
Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est distribué
en version anglaise seulement.
To expedite distribution, this document is circulated as received from the committee secretariat.
ISO Central Secretariat work of editing and text composition will be undertaken at publication
stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.
THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE
REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT, WITH THEIR COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPORTING DOCUMENTATION.
©
International Organization for Standardization, 2008

---------------------- Page: 1 ----------------------
ISO/DIS 9683-2
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall
not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the
unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
Copyright notice
This ISO document is a Draft International Standard and is copyright-protected by ISO. Except as permitted
under the applicable laws of the user's country, neither this ISO draft nor any extract from it may be
reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, photocopying,
recording or otherwise, without prior written permission being secured.
Requests for permission to reproduce should be addressed to either ISO at the address below or ISO's
member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Reproduction may be subject to royalty payments or a licensing agreement.
Violators may be prosecuted.
©
ii ISO 2008 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/DIS 9683-2
Contents Page
Foreword .iv
Introduction.iv
1 Scope.1
2 Normative references.1
3 Principle.1
3.1 Dissolution .1
3.2 Determination .2
3.2.1 Extraction (Method 1 only) .2
3.2.2 Measurement (Methods 1 and 2).2
4 Reagents .2
5 Apparatus.3
6 Sampling and samples.4
6.1 Laboratory sample .4
6.2 Preparation of predried test samples.4
7 Procedure.4
7.1 Number of determinations.4
7.2 Safety precautions .5
7.3 Test portion.5
7.4 Blank test and check test .5
7.5 Determination Method 1 [vanadium content between 0,005 (m/m) and 0,05 (m/m)]. .5
7.5.1 Decomposition of the test portion.5
7.5.2 Dissolution of salts and residue treatment.5
7.5.3 Extraction of vanadium.6
7.5.4 Adjustment of the atomic absorption spectrometer.6
7.5.5 Atomic absorption measurements .6
7.6 Determination Method 2 [vanadium content between 0,05% (m/m) and 0,5% (m/m)].7
7.6.1 Decomposition of the test portion.7
7.6.2 Dissolution of salts and residue treatment.7
8 Expression of results.7
8.1 Calculation of vanadium content.7
8.2 General treatment of results .7
8.2.1 Repeatability and permissible tolerance.7
8.2.2 Determination of analytical result.8
8.2.3 Between-laboratories precision.8
8.2.4 Check for trueness.9
8.2.5 Calculation of final result.9
8.3 Oxide factor.10
9 Test report.10
Annex A (normative) Flowsheet of the procedure for the acceptance of analytical values for test
samples .11
Annex B (informative) Derivation of repeatability and permissible tolerance equations.12
Annex C (informative) Precision data obtained by international analytical trials.13

© ISO 2008 – All rights reserved iii

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ISO/DIS 9683-2
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 9683-2 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron,
Subcommittee SC 2, Chemical analysis.
This second/third/. edition cancels and replaces the first/second/. edition (ISO 9684:1991), [clause(s) /
subclause(s) / table(s) / figure(s) / annex(es)] of which [has / have] been technically revised.
ISO 9683 consists of the following parts, under the general title Iron ores — Determination of vanadium
content:
⎯ Part 1: BPHA spectrophotometric methods
⎯ Part 2: Flame atomic absorption spectrometric methods
iv © ISO 2008 – All rights reserved

---------------------- Page: 4 ----------------------
DRAFT INTERNATIONAL STANDARD ISO/DIS 9683-2

Iron ores — Determination of vanadium —
Part 2:
Flame atomic absorption spectrometric methods
WARNING — This part of ISO 9683 may involve hazardous materials, operations and equipment. This
part of ISO 9683 does not purport to address all of the safety issues associated with its use. It is the
responsibility of the user to establish appropriate health and safety practices and determine the
applicability of regulatory limitations prior to use.
1 Scope
This part of ISO 9683 specifies two flame atomic absorption spectrometric methods for the determination of
the vanadium content of iron ores.
Method 1 is applicable to vanadium contents between 0,004% (m/m) and 0,06% (m/m), and Method 2 to
vanadium contents between 0,06% (m/m) and 0,5% (m/m) in natural iron ores, iron ore concentrates and
agglomerates, including sinter products.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 648, GenLaboratory glassware — One-mark pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3082, Iron ores — Sampling and sample preparation procedures
ISO 7764, Iron ores — Preparation of predried test samples for chemical analysis
3 Principle
3.1 Dissolution
The test portion is decomposed by digestion with hydrochloric acid in a polytetrafluoroethylene (PTFE) beaker,
hydrofluoric and nitric acids are added and the solution is evaporated to dryness. Hydrochloric and boric acids
are added and the solution is again evaporated to dryness. The salts are dissolved in hydrochloric and nitric
acids (Method 1), or hydrochloric acid (Method 2), and the solution is filtered. The residue is ignited and fused
with sodium carbonate and the cooled melt is dissolved in the test solution.
© ISO 2008 – All rights reserved 1

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ISO/DIS 9683-2
3.2 Determination
3.2.1 Extraction (Method 1 only)
The solution is oxidized with cerium(IV) solution and phosphoric acid and sodium tungstate solution are added.
The vanadium complex is extracted with a 1 + 1 mixture of 1-pentanol and 4-methyl-2-pentanone. The solvent
phase is treated with water and then ascorbic acid solution to return the vanadium to an aqueous phase.
3.2.2 Measurement (Methods 1 and 2)
Aluminium solution is added to the test solution, which is diluted to volume. The solution is aspirated into a
dinitrogen oxide acetylene-flame in an atomic absorption spectrometer and the absorbance is measured at a
wavelength of approximately 318,5 nm.
4 Reagents
During the analysis, use only reagents of recognized analytical grade, and only distilled water or water of
equivalent purity.
4.1 Hydrochloric acid, ρ1,16 g/ml to 1,19 g/ml.
4.2 Hydrochloric acid, ρ1,16 g/ml to 1,19 g/ml, diluted 1 + 1.
4.3 Hydrofluoric acid, ρ1,13 g/ml, 40% (m/m) or 1,19 g/ml, 48% (m/m).
4.4 Nitric acid, ρ1,4 g/ml.
4.5 Nitric acid, ρ1,4 g/ml, diluted 1 + 1. (Method 1 only.)
4.6 Phosphoric acid, ρ 1,7 g/ml, diluted 1 + 2. (Method 1 only.)
4.7 Sodium carbonate, Na CO , anhydrous powder.
2 3
4.8 Boric acid (H BO )
3 3
4.9 Di-ammonium cerium(IV) nitrate, [(NH ) Ce(NO ) ], 20 g/l solution. (Method 1 only.)
4 2 3 6
Dissolve 2,0 g of di-ammonium cerium(IV) nitrate in a mixture of 15 ml of nitric acid (4.5) and 85 ml of water.
4.10 4.10 Sodium tungstate, (Na WO .2H O), 165 g/l solution. (Method 1 only.)
2 4 2
Dissolve 16,5 g of sodium tunstate dihydrate in approximately 70 ml of water, dilute to 100 ml and mix.
4.11 Ascorbic acid, (C H O ), 10 g/l solution. (Method 1 only.)
6 8 6
Prepare freshly for each series of tests.
4.12 I-Pentanol, (n-amyl alcohol, 1-pentan-1-ol). (Method 1 only.)
4.13 4-Methyl-2-pentanone, (methyl isobutyl ketone, MIBK). (Method 1 only.)
4.14 Mixed solvent. (Method 1 only.)
Prepare a 1 + 1 volume ratio mixture of pentan-1-ol (4.12) and MIBK (4.13).
4.15 Aluminium chloride (AlCl .6H O), 220 g/litre solution.
3 2
2 © ISO 2008 – All rights reserved

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ISO/DIS 9683-2
Dissolve 220 g of aluminium chloride hexahydrate in water, add 50 ml of hydrochloric acid (4.1), dilute to
1000 ml with water and mix.
4.16 Iron oxide, high purity (containing less than 0,002% V).
4.17 Iron background solution. (Method 2 only.)
Dissolve 90 g of high purity iron oxide (4.16) in 750 ml of hydrochloric acid (4.1) while heating. Cool and
carefully add a solution of 30 g of sodium carbonate (4.7) in 200 ml of water. Dilute with water to a final
volume of approximately 1000 ml and mix.
NOTE The use of an equivalent quantity of metallic iron (of similarly low vanadium content) in conjunction with a
suitable oxidant is permissible.
4.18 Standard vanadium solution, 1 mg V/ml.
Dry ammonium monovanadate (NH VO ) in an air oven at 100 ºC for 1 h and cool to room temperature.
4 3
Dissolve 2,296 g of the dried product in approximately 600 ml of water, transfer to a 1 000 ml one-mark
volumetric flask, dilute to volume with water and mix.
4.19 Diluted standard vanadium solution, 0,2 mg V/ml. (Method 1 only.)
Transfer 20,0 ml of vanadium standard solution (4.18) to a 100 ml one-mark volumetric flask, dilute to volume
with water and mix.
4.20 Vanadium calibration solutions. (Method 1 only.)
Transfer 1,8 g of high purity iron oxide (4.16) to each of five 100 ml PTFE beakers (5.1). Proceed according to
7.5.1, incorporating the operation in 7.5.2 to dissolve the evaporated salts.
Transfer 0 ml; 1,00 ml; 2,00 ml: 4,00 ml and 6,00 ml of the diluted standard vanadium solution (4.19)
respectively to the beakers. Omit the residue processing steps and add 10 ml of nitric acid (4.5) and 25 ml of
water. Evaporate to 50 ml and proceed as specified in 7.5.3.
4.21 Vanadium calibration solutions. (Method 2 only.)
Transfer 0 ml; 1,00 ml; 2,00 ml; 4,00 ml and 6,00 ml of vanadium standard solution (4.18) respectively to five
100 ml one-mark volumetric flasks. Add 10 ml of iron background solution (4.17), 4,0 ml of aluminium solution
(4.15) and 0,5 g of boric acid (4.8) to each flask. Dilute to volume with water and mix.
5 Apparatus
Ordinary laboratory equipment, including one-mark pipettes and one mark-volumetric flasks complying with
the specifications of ISO 648 and ISO 1042 respectively (unless otherwise indicated), and
5.1 Polytetrafluoroethylene (PTFE) beakers, of capacity 100 ml, preferably low form.
5.2 Platinum crucibles, of minimum capacity 20 ml.
5.3 Muffle furnace.
5.4 Separating funnels, 100 ml (preferably graduated).
5.5 Atomic absorption spectrometer, equipped with a dinitrogen oxide-acetylene burner.
The atomic absorption spectrometer used in this method is satisfactory if it meets the following criteria:
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ISO/DIS 9683-2
a) Minimum sensitivity — the absorbance of the most concentrated vanadium calibration solution (4.21) is at
least 0,25 (see note 4).
b) Graph linearity — the slope of the calibration graph covering the top 20% of the concentration range
(expressed as a change in absorbance) is not less than 0,7 of the value of the slope for the bottom 20%
of the concentration range determined in the same way.
c) Minimum stability — the standard deviation of the absorbance of the most concent
...